*,
:before,
:after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
body,
html {
  width: 100%;
  height: 100%;
}

ol,
ul {
  list-style: none;
}
a {
  text-decoration: none;
}

//那个想要就添加到父级元素上
.clearfix {
  &:after {
    visibility: hidden;
    display: block;
    font-size: 0;
    content: ' ';
    clear: both;
    height: 0;
  }
}
